The Molecular Mechanism of Human Voltage-Dependent Anion Channel 1 Blockade by the Metallofullerenol Gd@C(82)(OH)(22): An In Silico Study

The endohedral metallofullerenol Gd@C(82)(OH)(22) has been identified as a possible antineoplastic agent that can inhibit both the growth and metastasis of cancer cells. Despite these potentially important effects, our understanding of the interactions between Gd@C(82)(OH)(22) and biomacromolecules remains incomplete. Here, we study the interaction between Gd@C(82)(OH)(22) and the human voltage-dependent anion channel 1 (hVDAC1), the most abundant porin embedded in the mitochondrial outer membrane (MOM), and a potential druggable target for novel anticancer therapeutics. Using in silico approaches, we observe that Gd@C(82)(OH)(22) molecules can permeate and form stable interactions with the pore of hVDAC1. Further, this penetration can occur from either side of the MOM to elicit blockage of the pore. The binding between Gd@C(82)(OH)(22) and hVDAC1 is largely driven by long-range electrostatic interactions. Analysis of the binding free energies indicates that it is thermodynamically more favorable for Gd@C(82)(OH)(22) to bind to the hVDAC1 pore when it enters the channel from inside the membrane rather than from the cytoplasmic side of the protein. Multiple factors contribute to the preferential penetration, including the surface electrostatic landscape of hVDAC1 and the unique physicochemical properties of Gd@C(82)(OH)(22). Our findings provide insights into the potential molecular interactions of macromolecular biological systems with the Gd@C(82)(OH)(22) nanodrug.